Ideally, during the exposure period when an image is captured, each pixel of the imaged scene is focused by the camera optics onto a particular sensel of the camera sensor.
However, if the camera moves during the exposure period the pixels from the imaged scene may be focused by the optics not only onto their particular sensels but also other sensels. This may create blurring in a rendered image.
This problem becomes greater when long exposure periods are used.
This problem has typically been addressed either by using ‘at-capture’ image stabilization such as optical image stabilization or ‘post-capture’ image stabilization such as electrical image stabilization or digital image stabilization.
Optical image stabilization adjusts the configuration of the camera during the exposure period so that movement of the camera is at least partially compensated. The purpose of optical image stabilization is to make adjustments to the configuration of the camera during the exposure period to try and direct the pixels from the imaged scene on to only their own particular sensels.
In contrast, digital image stabilization may, for example, track movement of the scene relative to the image sensor at a macro-level. Using digital image processing the consequence of this movement on the high resolution image can be at least partially filtered out of the captured high resolution image. A series of low resolution images, captured simultaneously with a high resolution (longer exposure) image may be used to track movement of the scene, for example.
Electronic image stabilization may, for example, track movement of the scene relative to the image sensor at a macro-level. The image may be shifted in the image plane, frame by frame, so that wobble is removed.